Tahmir Craig smiled as he stood outside Wednesday afternoon. The 23-year-old man had good reason to. It was the first time he had seen the light of day since spending nine months in prison for a crime that he didn't commit.

Last Memorial Day, Police responded to the 2100 block of Edgmont Avenue in Chester for a reported shooting. When they arrived they found the body of 27-year-old Devon Williams. Police obtained surveillance video showing a man chasing Williams on Edgmont near 21st Street and then shooting him to death in broad daylight.

Within hours of the shooting, police say they received information that the suspect’s name was “Tahmir.” Several witnesses identified Craig as the shooter in the surveillance video. He was arrested on June 4 and remanded to Delaware County Prison without bail. Police say they based the arrest on probable cause and witness testimony.

As police continued to investigate, they sent still images of the shooter to Delaware State Police, the U.S. Marshals and the FBI. Using facial recognition technology and forensic video analysis, officials determined that Craig was not the shooter in the video and had been wrongly accused of murder. Investigators say special software showed that the killer stands at 5-foot-11. Tahmir is only 5-foot-5. All charges against Craig were then dropped. Delaware County District Attorney Jack Whelan announced the withdrawn charges on Wednesday.

“As prosecutors in the administration of justice, we have an absolute duty to exhaust all resources in our efforts to pursue the truth,” said Whelan. “After thorough investigation and assistance from the FBI, we were able to confirm that Tahmir Craig is not the shooter and immediately released him from prison.”

Craig was released from prison Wednesday afternoon. His mother, Melonie Craig, stood by his side as he spoke to NBC10's Deanna Durante.

"From the beginning I knew my son didn't do it," said Melonie while fighting back tears. "The city of Chester knows my son didn't do it."

Craig says he is thankful for everything his mother did for him.

"She worked real hard to pay my lawyer when nobody else put money up," he said. "She's all I got."

While Craig admitted that he was a "little" angry at the witnesses who claimed he was the shooter, he also said that he'd "be alright." Still, Craig's attorney, who claimed he told police from the start that investigators had the wrong man, says preparations are underway to file a civil suit against Delaware County. Whelan says he made the effort to reach out to Craig after the charges were dropped.

"I met with Tahmir Craig today and I met with his mother," said Whelan. "I apologized that they had to go through the criminal justice system and I apologized for the error that occurred."

Craig says he accepts Whelan's apology. He plans to eventually enroll into a community college and study business.

Meanwhile, the man who killed Williams still has not been found. Anyone with information on the shooting should call Detective Michael Jay at 610-891-4711 or Chester Police Detective Nelson Collins at 610-447-8431.